震旦系—下寒武统白云岩优势成岩—成储效应——深层白云岩成因及差异成储  

Profitable Diagenetic Path and Reservoir Formation Efficiency of the Sinian-Lower Cambrian Dolostone:Origins of deep dolomites and differential reservoir formation

作　　者：刘媛媛 王子晨 明鑫雨 姜磊 LIU YuanYuan;WANG ZiChen;MING XinYu;JIANG Lei(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Lithospheric and Environmental Coevolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;College of Resources and Environment,Yangtze University,Wuhan 430100,China)

机构地区：[1]成都理工大学沉积地质研究院,成都610059 [2]中国科学院地质与地球物理研究所岩石圈演化与环境演变全国重点实验室,北京100029 [3]中国科学院大学地球与行星科学学院,北京100049 [4]长江大学资源与环境学院,武汉430100

出　　处：《沉积学报》2024年第6期2159-2173,共15页Acta Sedimentologica Sinica

基　　金：中国科学院战略性先导科技专项(XDA0430202)。

摘　　要：【目的】深层—超深层碳酸盐岩具有巨大的油气勘探潜力。由于经历了复杂的成岩改造,其储层具有非均质性强、预测困难等显著特征。因此,厘清优势成岩作用对储层的差异性改造,即优势成储效应,是揭示深部碳酸盐岩储层成因的关键。【方法】基于系统对比四川盆地和塔里木盆地(含少量阿曼盆地和西伯利亚台地数据)震旦系—下寒武统白云岩储层地球化学参数及孔隙度与渗透率,包括碳氧同位素(n=617)、锶同位素(n=189)、稀土元素(n=106)、流体包裹体均一化温度(n=161)、团簇同位素温度(n=117)和孔隙度与渗透率(n=1557),建立了两个层系储层不同成因白云石和晚期方解石的地球化学特征模板。【结果】两个层系储层成岩矿物的地球化学特征总体上具有较高的相似性,均经历了白云石化、大气水、裂隙、热液作用等具建设性意义的成岩改造过程。而与下寒武统白云岩储层相比,区内储层质量最高的灯影组经历的渗透回流白云石化作用及后期热液流体改造作用最强,表明差异性成岩改造是成储效应优劣的关键。【结论】综合上述特点,提出四川盆地和塔里木盆地震旦系—寒武系优质白云岩储层的发育主要受沉积期蒸发作用及晚期构造热液发育程度共同控制。该认识可用于深层—超深层碳酸盐岩储层预测,对深部油气勘探具有重要的启示意义。[Objective]Deep-ultra-deep carbonate rocks have great potential in oil and gas exploration,and their reservoirs are characterized by strong heterogeneity and difficult prediction,which is closely related to their complex diagenetic alterations.Therefore,clarifying the beneficial diagenetic processes in reservoir development,that is,profitable diagenetic path and reservoir formation efficiency,is the key to revealing the genesis of deep carbonate reservoirs.[Methods]We have systematically compared the geochemical parameters,porosity,and permeability of the Sinian to lower Cambrian dolostone from the Sichuan Basin and Tarim Basin(including a small amount of data from the Oman Basin and Siberian Platform),including carbon and oxygen isotopes(n=617),strontium isotope(n=189),rare earth elements(n=106),fluid inclusion homogenization temperature(n=161),cluster isotope temperature(n=117),and porosity and permeability(n=1557).The geochemical feature templates of dolomite and late calcite of different origins in the two reservoirs were established.[Results]The results show that the geochemical characteristics of diagenetic minerals in the two reservoirs are similar,and both have undergone constructive diagenetic alterations such as dolomitization,meteoric water,fracturing,and hydrothermal fluids.Compared with the lower Cambrian dolostone reservoirs,the highest-quality reservoirs in the area(Dengying Formation)have experienced stronger seepage-reflux dolomitization,particularly the more intense hydrothermal alternations,suggesting that differential effective diagenetic alterations are the key to good carbonate reservoir formation.[Conclusions]Based on the above characteristics,the development of Sinian-Cambrian high-quality dolostone reservoirs in the Sichuan Basin and Tarim Basin is jointly controlled by the development of evaporite facies in the depositional period and the development of late structural hydrothermal fluids.The above findings can be used to predict deep-ultra-deep carbonate reservoirs,and have enlightenmen

关 键 词：深层—超深层油气勘探 碳酸盐岩 白云石化 成岩作用 孔隙演化 成储效应 

分 类 号：P588.245[天文地球—岩石学]